U.S. patent application number 12/742606 was filed with the patent office on 2011-05-05 for packet buffering method and apparatus for reducing packet loss in proxy mobile ipv6.
Invention is credited to Junghoon Jee, Hong Seok Jeon, Chang Min Park.
Application Number | 20110103304 12/742606 |
Document ID | / |
Family ID | 40638886 |
Filed Date | 2011-05-05 |
United States Patent
Application |
20110103304 |
Kind Code |
A1 |
Jeon; Hong Seok ; et
al. |
May 5, 2011 |
PACKET BUFFERING METHOD AND APPARATUS FOR REDUCING PACKET LOSS IN
PROXY MOBILE IPv6
Abstract
Disclosed are a packet buffering apparatus and method for
reducing packet loss in a proxy mobile IPv6, which include a first
Mobile Access Gateway (MAG) requesting a Local Mobility Anchor
(LMA) for packet buffering when outgoing Mobile Node (MN) being
served by the MAG is detected, and the LMA for buffering the packet
transmitted to the corresponding MN when receiving a request for
the packet buffering.
Inventors: |
Jeon; Hong Seok; (Daejeon,
KR) ; Jee; Junghoon; (Daejeon, KR) ; Park;
Chang Min; (Daejeon, KR) |
Family ID: |
40638886 |
Appl. No.: |
12/742606 |
Filed: |
September 3, 2008 |
PCT Filed: |
September 3, 2008 |
PCT NO: |
PCT/KR08/05173 |
371 Date: |
May 12, 2010 |
Current U.S.
Class: |
370/328 |
Current CPC
Class: |
H04W 36/02 20130101;
H04W 8/085 20130101; H04W 80/04 20130101 |
Class at
Publication: |
370/328 |
International
Class: |
H04W 4/00 20090101
H04W004/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 22, 2008 |
KR |
10-2007-0115226 |
Claims
1. A method for buffering a packet of a Local Mobility Anchor (LMA)
in a network based on a proxy mobile Internet Protocol (IP), the
method comprising: receiving a request for packet buffering when
detecting an outgoing mobile node from a first Mobile Access
Gateway (MAG); and buffering packets being transmitted to the
corresponding mobile node when receiving the request for the packet
buffering.
2. The method of claim 1, wherein the receiving receives the
request for the packet buffering using a Proxy Binding Update (PBU)
message in which a lifetime field value is `0` and a packet
buffering (B) flag is set.
3. The method of claim 2, further comprising: generating a Proxy
Binding Acknowledgement (PBA) message in which a packet buffering
(B) flag is set in response to the PBU message and transmitting the
generated PBA message to the first MAG transmitting the PBU
message, when receiving the PBU message requesting packet
buffering.
4. The method of claim 2, wherein the PBU message includes a packet
buffering (B) flag field indicating a packet being transmitted to
the corresponding mobile node is being buffered when set.
5. The method of claim 3, wherein the PBA message includes a packet
buffering (B) flag field indicating a response with respect to a
request for buffering the packet being transmitted to the
corresponding mobile node.
6. The method of claim 1, further comprising: identifying a mobile
node included in a PBU message to see whether the packets for the
corresponding mobile node are being buffered when receiving, from
the second MAG, the PBU message that indicates an incoming mobile
node; and transmitting the packets being buffered to the second MAG
when the packets to the corresponding mobile node are being
buffered according to the determined result.
7. A method for reducing packet loss of a Mobile Access Gateway
(MAG) in a network based on a proxy mobile IP, the method
comprising: ascertaining whether a mobile node served by the MAG
has been detached; and requesting a Local Mobility Anchor (LMA) for
packet buffering when the outgoing mobile node is detected
according to the ascertainment.
8. The method of claim 7, wherein the requesting requests the
packet buffering by transmitting a Proxy Binding Update (PBU)
message in which a lifetime field value is `0` and a packet
buffering (B) flag is set.
9. The method of claim 8, further comprising: verifying whether the
PBU message is normally processed by receiving a Proxy Binding
Acknowledgement (PBA) message from the LMA in which a packet
buffering (B) flag is set after requesting for the packet buffering
by transmitting the PBU message.
10. A network based on a proxy mobile Internet Protocol (IP) for
reducing packet loss, the network comprising: a first Mobile Access
Gateway (MAG) for requesting a Local Mobility Anchor (LMA) for
packet buffering when a mobile node served by the MAG has been
detached; and the LMA for buffering packets being transmitted to
the corresponding mobile node when receiving the request for the
packet buffering.
11. The network of claim 10, wherein the packet buffering is
requested by using a Proxy Binding Update (PBU) message in which a
lifetime field value is `0` and a packet buffering (B) flag is
set.
12. The network of claim 11, wherein when receiving the PBU message
requesting the packet buffering, the LMA generates a Proxy Binding
Acknowledgement (PBA) message in which a packet buffering (B) flag
is set in response to the PBU message and transmits the generated
PBA message to the first MAG transmitting the PBU message.
13. The network of claim 11, wherein the PBU message includes a
packet buffering (B) flag field indicating whether packets for the
corresponding mobile node are buffered or not.
14. The network of claim 12, wherein the PBA message includes a
packet buffering (B) flag field indicating a response with respect
to a request for buffering the packets for the corresponding mobile
node.
15. The network of claim 10, further comprising: a second MAG for
generating a PBU message indicating the incoming mobile node when
the incoming mobile node is detected, and transmitting the
generated PBU message to the LMA, wherein when receiving, from the
second MAG, the PBU message that indicates the incoming mobile
node, the LMA verifies whether the packets to the corresponding
mobile node are being buffered, and transmits the packets being
buffered to the second MAG according to the verified result.
16. The method of claim 3, wherein the PBU message includes a
packet buffering (B) flag field indicating a packet being
transmitted to the corresponding mobile node is being buffered when
set.
17. The network of claim 12, wherein the PBU message includes a
packet buffering (B) flag field indicating whether packets for the
corresponding mobile node are buffered or not.
Description
TECHNICAL FIELD
[0001] The present invention relates to a packet buffering method
and apparatus for reducing packet loss in a proxy mobile Internet
Protocol version 6 (IPv6), and more particularly, to a packet
buffering method and apparatus for reducing packet loss in an IPv6
based-radio access network, which may buffer a packet to be
transmitted from a Local Mobility Anchor (LMA) to a Mobile Node
(MN) when the MN is moved between Mobile Access Gateways
(MAGs).
[0002] This work was supported by the IT R&D program of
MIC/IITA. [2007-P10-01, A Study on Mobility Management in Next
Generation Mobile Networks]
BACKGROUND ART
[0003] The present invention relates to a packet buffering method
and apparatus for reducing packet loss in a proxy mobile Internet
Protocol version 6 (IPv6), and more particularly, to a packet
buffering method and apparatus for reducing packet loss in an
IPv6-based radio access network.
[0004] As a Mobile Node (MN) is moved, according to Request for
Comments (RFC) 3344 standardized in an IETF (Internet Engineering
Task Force), `IP Mobility Support for IPv4` (Mobile IPv4) and RFC
3775, and `Mobility Support in IPv6` (Mobile IPv6), location
information of the MN may be directly registered in a Home Agent
(HA), thereby updating a data path depending on the mobility of the
MN. The mobility of the Mobile IPv4/Mobile IPv6 may request the MN
for performing separate functions with respect to the corresponding
operation and management of various information used for Mobile
IPv4/Mobile IPv6 operations. A purpose of the proxy mobile IP is to
provide IP mobility services based on a network without requesting
the MN for the above-described requirements. Specific components of
a network in the proxy mobile IP (for example, access point or base
station) may detect the mobility of the MN and perform a location
information registration process on behalf of the MN.
[0005] FIG. 1 is a flowchart illustrating operations of a Proxy
Mobile IPv6 standardized in the IETF NETLMM working group.
Referring to FIG. 1, a Proxy Mobile IPv6 Domain (PMIPv6 Domain)
includes a Mobile Node (MN) 100, a Mobile Access Gateway (MAG) 102,
and a Local Mobility Anchor (LMA) 104.
[0006] The PMIPv6 Domain may denote a range of an access network
providing IP mobility services to the MN 100 using a proxy mobile
IPv6 scheme. The LMA 104 may have a Home Agent (HA) function for
managing location information of all MNs being in service within
the corresponding PMIPv6 Domain. The location information of the MN
100 in the LMA 104 may adopt an IP address of the MAG 102 in which
the MN is currently in service as a Care of Address (CoA) to manage
in a Binding Cache Entry (BCE) form. Since the LMA 104 is
structured to be located in the upper level of data paths of all
MAGs, a path of data to be transmitted to the MN 100 is re-routed
as the MN 100 is moved between the MAGs, thereby supporting the IP
mobility service. The LMA 104 may manage MN-Home Network Prefix
(MN-HNP) information for each MN, so that it is simulated as the MN
100 is always in service in an identical sub-network although the
MN 100 is moved between the MAGs within the PMIPv6 Domain (that is,
between sub-networks). The MAG 102 may detect connection of the MN
with a Border Router (or Border Layer 2 device) of the access
network, and serve to register the location information of the
corresponding MN 100 in the LMA 104. For the purpose of registering
the location information, the MAG may use Proxy Binding
Update/Proxy Binding Acknowledgement (PBU/PBA) messages, that is,
expansion of Binding Update/Binding Acknowledgement (BU/BA)
messages of the existing Mobile IPv6. The MN 100 being in service
within the PMIPv6 Domain may be divided using an identifier such as
a Network Access Identifier (NAI) or a Fully Qualified Domain Name
(FQDN), which is used as an identifier used for acquiring
supplementary information of the MN such as MN-HNP information and
address generation method of the corresponding MN, and a roaming
policy. It is assumed that the supplementary information of the MN
is generally stored in an Authentication, Authorization and
Accounting (AAA) server, and all network nodes within the PMIPv6
Domain are capable of accessing the AAA server.
[0007] When the MN 100 is connected with the PMIPv6 Domain in
operation 106, the corresponding MAG may acquire identifier
information of the MN (MN-Id) through an authorization procedure.
The MAG 102 may acquire the supplementary information of the MN 100
through a communication with the AAA server using the identifier
information of the MN when detecting connection of the MN 100 with
the MAG 102 in operation 108, and then register the location
information of the MN 100 in the LMA 104 through a PBU message 110
and a PBA message 114 in operation 112. An IP tunnel 118 used for
data transmission of the MN 100 may be generated between the LMA
104 and the MAG 102 after a registration procedure is successfully
performed by receiving the PBA message 114 from the MAG 102 in
operation 116, and then routing information for the LMA 104 and the
MAG 102 is added in the LMA 104 and the MAG 102, respectively.
[0008] Next, the MAG 102 may transmit a Router Advertisement (RA)
message 122 for providing, to the MN, information (Prefix, Hop
Limit Value, Address Configuration mode) about the sub-network for
advertising or managing transmission by the sub-network in response
to a Router Solicitation (RS) message 120, and thereby the MN 100
may compose an IP address in operation 124. Meanwhile, the MN 100
may transmit the RS message 120 to the MAG 102 in order to quickly
receive the RA message 122 when failing to receiving the RA message
122 within a given time interval.
[0009] The above-described processes may be repeatedly performed as
the MN 100 is moved between the MAGs within the PMIPv6 Domain.
[0010] The proxy mobile IPv4 is to provide IP mobility services
based on a network without participation of the MN in the IPv4
based-access network.
[0011] The proxy mobile IPv6 may reduce deterioration of
performance of the IP mobility service due to delay of a movement
detection procedure of the existing Mobile IPv6, delay of a CoA
configuration procedure, delay of a location information binding
update procedure, and the like. However, there still remains a
problem of the performance deterioration of the IP mobility service
due to delay of mobility procedure of layer 2. Also, movement
between the existing networks or delay occurring due to an access
authentication process may aggravate the delay of mobility
procedure of the layer 2.
[0012] Thus, there is a need for an apparatus and method for
minimizing packet loss of the MN due to delay of the IP mobility
service capable of occurring in the proxy mobile IPv6.
DISCLOSURE OF INVENTION
Technical Problem
[0013] An aspect of the present invention provides a packet
buffering method and apparatus for reducing packet loss in a proxy
mobile Internet Protocol version 6 (IPv6).
[0014] Another aspect of the present invention provides a packet
buffering method and apparatus for reducing packet loss in an IPv6
based-radio access network, which may buffer a packet to be
transmitted from a Local Mobility Anchor (LMA) to a Mobile Node
(MN) when the MN is moved between Mobile Access Gateways
(MAGs).
[0015] Still another aspect of the present invention provides a
packet buffering method and apparatus, which may request a LMA for
buffering a packet transmitted to a MN when the MN is out of
service the MAG provides.
TECHNICAL SOLUTION
[0016] According to an aspect of the present invention, there is
provided a method for buffering a packet of a Local Mobility Anchor
(LMA) in a network based on a proxy mobile Internet Protocol (IP),
the method including: receiving a request for packet buffering when
detecting an outgoing mobile node from a first Mobile Access
Gateway (MAG); and buffering packets being transmitted to the
corresponding mobile node when receiving the request for the packet
buffering.
[0017] According to another aspect of the present invention, there
is provided a method for reducing packet loss of a MAG in a network
based on a proxy mobile IP, the method including: ascertaining
whether a mobile node served by the MAG has been detached; and
requesting a LMA for packet buffering when the outgoing mobile node
is detected according to the ascertainment.
[0018] According to still another aspect of the present invention,
there is provided a network based on a proxy mobile IP for reducing
packet loss, the network including: a first MAG for requesting a
LMA for packet buffering when a mobile node served by the MAG has
been detached; and the LMA for buffering a packet being transmitted
to the corresponding mobile node when receiving the request for the
packet buffering.
[0019] The foregoing descriptions of specific embodiments of the
present invention have been presented for purposes of illustration
and description. They are not intended to be exhaustive or to limit
the invention to the precise forms disclosed, and obviously many
modifications and variations are possible in light of the above
teaching. Therefore, it is intended that the scope of the invention
be defined by the claims appended thereto and their
equivalents.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 is a flowchart illustrating operations of a proxy
mobile Internet Protocol version 6 (IPv6) standardized in the IETF
NETLMM working group;
[0021] FIG. 2 is a diagram illustrating a proxy mobile IPv6-based
network structure for packet buffering according to an exemplary
embodiment of the present invention;
[0022] FIG. 3 is a flowchart illustrating a flow of a message for
packet buffering when a mobile node is moved between Mobile Access
Gateways (MAGs) in a proxy mobile IPv6 based-network according to
an exemplary embodiment of the present invention;
[0023] FIG. 4 is a diagram illustrating a format of a Proxy Binding
Update (PBU) message according to an exemplary embodiment of the
present invention;
[0024] FIG. 5 is a diagram illustrating a format of a Proxy Binding
Acknowledgement (PBA) message according to an exemplary embodiment
of the present invention;
[0025] FIG. 6 is a flowchart illustrating a packet buffering
requesting process of a MAG in a proxy mobile IPv6 network
according to an exemplary embodiment of the present invention;
and
[0026] FIG. 7 is a flowchart illustrating a packet buffering
process of a Local Mobility Anchor (LMA) in a proxy mobile IPv6
network according to an exemplary embodiment of the present
invention.
MODE FOR THE INVENTION
[0027] Reference will now be made in detail to embodiments of the
present invention, examples of which are illustrated in the
accompanying drawings, wherein like reference numerals refer to the
like elements throughout. The embodiments are described below in
order to explain the present invention by referring to the
figures.
[0028] The present invention relates to a packet buffering method
and apparatus for reducing packet loss in a proxy mobile Internet
Protocol version 6 (IPv6) based-radio access network, in which a
Local Mobility Anchor (LMA) buffers packets destined for a Mobile
Node (MN) when the MN moves between Mobile Access Gateways (MAGs),
and the apparatus will be described in detail with reference to
FIG. 2.
[0029] FIG. 2 is a diagram illustrating a proxy mobile IPv6-based
network structure for packet buffering according to an exemplary
embodiment of the present invention. Referring to FIG. 2, the proxy
mobile IPv6 based-network of the present exemplary embodiment of
the invention includes a Local Mobility Anchor (LMA) 200, a first
Mobile Access Gateway (MAG) 210, a first Access Point (AP) 212, a
second MAG 220, a second AP 222, a Mobile Node (MN) 230, a policy
store 240, and a correspondent node 250.
[0030] The first MAG 210 in the proxy mobile IPv6 based-network
according to the present exemplary embodiment of the invention
requests the LAM for packet buffering when detecting the MN 230 not
being served by the MAG any more because the MN 230 moves to a
service region of the second MAG 220. Next, the LAM buffers packets
transmitted to the MN 230 when receiving the request for the packet
buffering, and transmits the buffered packet to the MN 230 through
the second MAG 220 when establishing a bidirectional tunnel with
the second MAG 220. The packet buffering method when the MN 230
moves between the MAGs will be herein described in detail with
reference to FIG. 3.
[0031] FIG. 3 is a flowchart illustrating a flow of a message for
packet buffering when a mobile node is moved between Mobile Access
Gateways (MAGs) in a proxy mobile IPv6 based-network according to
an exemplary embodiment of the present invention.
[0032] Referring to FIG. 3, when the MN 230 is provided with packet
services by communicating with the LMA 200 through the first MAG
210 in operation 302 and then is not provided with the packet
services any more from the first MAG 210 due to movement of the MN
230, the first MAG 210 may detect the outgoing MN 230 in operation
304, generate a Proxy Binding Update (PBU) message 306 in which a
lifetime field value is set to `0` and a packet buffering flag is
set, and transmit the generated PBU message 306 to the LMA 200.
[0033] The LMA 200 generates a Proxy Binding Acknowledgement (PBA)
message 308 when ascertaining that the lifetime field value of the
received PBU message 306 is `0` and the packet buffering flag is
set, transmits the generated PBA message 308 to the first MAG,
marks the MN 230 whose packets are being buffered in a Binding
Cache Entry (BCE) in operation 310 and perform a buffering
operation for the packets destined to the MN 230. When the LMA 200
does not receive a PBU message 324, transmitted for registering
location information of the corresponding MN, for a specific time
interval, the buffering operation is stopped and all the buffered
packets are discarded. Meanwhile, configuration of the PBU message
306 and PBU message 308 will be described in detail with reference
to FIGS. 4 and 5.
[0034] The second MAG 220 may obtain information about incoming MN
230s from the policy store 240 in advance. The obtained information
consists of an address of the LMA 200 to which the MN 230 intends
to connect, an identifier of the MN 230, and so on. The policy
store 240 is a logical component where various setting,
information, and the like each required for PMIPv6 operations are
stored, and it may exist in an Authentication, Authorization and
Accounting (AAA) server. Operation 312 and receiving of various
setting and information 314 may occur when the second MAG 220
detects incoming MN 230 in advance, which otherwise may not
occur.
[0035] Meanwhile, the MN 230 performs handover in operation 316,
and then performs an authentication procedure 318 with the second
MAG 220.
[0036] The second MAG 220 obtains information about attached MN 230
from the policy store 240. The obtained information consists of
identification (ID) information 322 of the MN 230, an address of
the LMA 200 to which the MN 230 intends to connect and so on. When
operations 312 and 314 were performed, operation 322 may be
omitted. Then, the second MAG 220 transmits, to the LMA 200, the
PBU message 324 in which a lifetime field value is not `0`
according to a general proxy mobile IPv6 procedure.
[0037] The LMA 200 retrieves BCE information to see whether packets
for the corresponding MN are being buffered based on the ID
information of the MN 230 included in the PBU message 324, when
verifying that the lifetime field value of the received PBU message
324 is not `0`. Then, when the packets for the corresponding MN are
being buffered according to the checked result, the LMA 200
transmits the corresponding buffered packets to the second MAG 220
in operation 332.
[0038] FIG. 4 is a diagram illustrating a format of a Proxy Binding
Update (PBU) message according to an exemplary embodiment of the
present invention. Referring to FIG. 4, the PBU message according
to the present exemplary embodiment of the invention includes a
sequence number field 401, an Acknowledge (A) field 402, a
Link-Local Address Compatibility (L) field 406, a Key Management
Mobility Capability (K) field 408, a MAP Registration Flag (M)
field 410, a Mobile Router Flag (R) field 412, a Proxy Registration
Flag (P) field 414, a Packet Buffering Flag (B) field 416, a
reserved field 418, a lifetime field 420, and a mobility option
field 422.
[0039] In the sequence number field 401, values indicating a
sequence number of the PBU message are recorded. The sequence
number field 401 may be used for guaranteeing that continued PBU
messages are accurately transmitted in order. In A field 402,
values requesting for transmitting the PBA message while
simultaneously receiving the PBU message may be recorded. H field
404 may be used for indicating that the PBU message is transmitted
to a Home Agent (HA). L field 406 may be used for indicating that
an Interface Identifier of a link local address of the MN is the
same as an Interface Identifier of a home address of the MN. K
field 408 may be used for indicating that a protocol for security
association setting between the MN and the HA is reused every time
the MN is moved.
[0040] In M field 410, values indicating whether the corresponding
PBU message in a Hierarchical Mobile IP (HMIP) protocol is
transmitted with respect to a Mobility Anchor Point (MAP) different
from either the HA or a Corresponding Node (CN) may be recorded. In
R field 412, values informing the HA whether the corresponding PBU
message in a Network Mobility (NEMO) protocol is transmitted from a
Mobile Router may be recorded. In P field 414, values indicating
that the corresponding PBU message in the Proxy Mobile IPv6
protocol (PMIP 6) is used for proxy registration may be
recorded.
[0041] The reserved field 418 is a field being not used and
reserved. In the lifetime field 420, values indicating a lifetime
of binding may be recorded. When the lifetime field value is `0`,
the corresponding BCE of the MN may be eliminated. In the mobility
option field 422, values indicating mobility options such as
binding authorization data option, nonce indices option,
alternative Care Of Address (COA) option, and the like may be
recorded.
[0042] Also, a packet buffering (B) field 416 which is newly added
according to the present exemplary embodiment of the invention is
used for requesting the LMA for buffering packets destined for a
specific MN. When the LMA receives the PBU message in which B field
416 is set to `1`, packets transmitted to the corresponding MN are
buffered based on MN information informed through the corresponding
PBU message. In FIG. 4, remaining fields except B field 416 may
follow a conventional standard.
[0043] FIG. 5 is a diagram illustrating a format of a Proxy Binding
Acknowledgement (PBA) message according to an exemplary embodiment
of the present invention. Referring to FIG. 5, the PBA message
according to the present exemplary embodiment of the invention
includes a status field 501, a Key Management Mobility Capability
(K) field 502, a Mobile Router Flag (R) field 504, a Proxy
Registration Flag (P) field 506, a Packet Buffering Flag (B) field
508, a reserved field 510, a sequence number field 512, a lifetime
field 514, and a mobility option field 516.
[0044] In the status field 501, values indicating a processed
result of binding update of an MN may be recorded. K field 502 may
be used for indicating that a protocol for security association
setting between the MN and the HA is reused every time the MN is
moved. In R field 504, values indicating that the corresponding PBA
message in the NEMO protocol is used as a response from the LMA
with respect to the PBU message transmitted from the MGA may be
recorded. In P field 506, values indicating that the PBA message in
the PMIP6 protocol is used as a response with respect to proxy
registration request may be recorded.
[0045] The reserved field 510 is a field being not used and
reserved. In the sequence number field 512, values indicating a
sequence number of the PBU message may be recorded. The sequence
number field 512 may be used for matching the PBU message with the
PBA message, that is, a response to the PBU message. In the
lifetime field 514, values indicating a lifetime of binding may be
recorded. In the mobility option field 516, values indicating
mobility options such as binding authorization data option, binding
refresh advice option, and the like may be recorded.
[0046] Also, a packet buffering (B) field 508 newly added according
to the present exemplary embodiment of the invention is used for
indicating that the corresponding PBA message is a response to the
PBU message requesting the LMA for buffering packets destined for a
specific MN. In FIG. 5, remaining fields except B field 508 may
follow a conventional standard.
[0047] Hereinafter, the packet buffering method for reducing packet
loss in the proxy mobile IPv6 according to the present invention
constructed as described above will be described in detail with
respect to FIG. 6.
[0048] FIG. 6 is a diagram illustrating a packet buffering
requesting process of a MAG in a proxy mobile IPv6 network
according to an exemplary embodiment of the present invention.
Referring to FIG. 6, in operation 600, the MAG according to the
present exemplary embodiment of the invention establishes a
bidirectional tunnel with the LMA, transmits/receives packets
transmitted to the MN, and provides packet services to the MN.
Next, the MAG may ascertain whether the outgoing MN is detected in
operation 602, and repeatedly provide the packet service in
operation 600 when the outgoing MN is not detected. In this
instance, the outgoing MN denotes that the MN is out of a service
region.
[0049] However, in operation 604, when the outgoing MN is detected,
the MAG generates a PBU message in which the packet buffering (B)
flag is set to `1` and a lifetime field value is `0`, and transmits
the generated PBU message to the LMA. Next, in operation 606, the
MAG confirms that the LMA receives the PBU message, by receiving
the PBA message in which the packet buffering (B) flag is set, and
terminate the algorithm.
[0050] FIG. 7 is a flowchart illustrating a packet buffering
process of a Local Mobility Anchor (LMA) in a proxy mobile IPv6
network according to an exemplary embodiment of the present
invention. Referring to FIG. 7, in operation 700, the LMA of the
present exemplary embodiment of the present invention receives the
PBU message whose lifetime is expired. Next, in operation 702, the
LMA verifies whether a packet buffering (B) flag of the received
PBU message is set to `1`. Then, when the packet buffering (B) flag
is not set to `1` according to the verified result, the received
PBU message is processed according to a convention procedure.
[0051] In operation 704, when the packet buffering (B) flag is set
to `1` according to the verified result, the LMA generates the PBA
message in which the packet buffering (B) flag is set to `1` in
response to the received PBU message, and transmits the generated
PBA message to the MAG transmitting the PBU message. In operation
706, the LMA verifies information about the MN included in the
received PBU message, and buffer a packet transmitted to the
corresponding MN.
[0052] Next, in operation 708, the LMA verifies whether the PBU
message whose lifetime is not expired is received. When the PBU
message is not received, the LMA may return to operation 706.
Meanwhile, when the PBU message of the MN performing a packet
buffering for a predetermined time interval is not received, the
packet buffering is stopped, and the packets being buffered are
discarded.
[0053] In operation 710, the LMA generates the PBA message in
response to the PBU message when receiving the PBU message whose
lifetime is not expired, and transmits the generated PBA message to
the MAG transmitting the PBU message. In operation 712, the LMA
verifies whether information about the MN included in the PBU
message to check whether a packet transmitted to the corresponding
MN is being buffered. In operation 714, when the packet is being
buffered according to the checked result, the LMA may transmit the
buffered packet data to the MAG transmitting the PBU message whose
lifetime is not expired through a bidirectional tunnel. In
operation 716, the LMA transmits packets for the MN using the MAG
connected through the bidirectional tunnel. When the packets for
the corresponding MN is not being buffered according to the checked
result of operation 712, the LMA provides a packet service to the
MN using the MAG connected through the bidirectional tunnel without
forwarding the buffered packets. Then, the algorithm of the present
invention is terminated.
[0054] As described above, according to the present invention,
there are provided the packet buffering apparatus and method for
reducing packet loss in the proxy mobile IPv6, which includes the
first MAG requesting the LMA for packet buffering when outgoing MN
being served by the MAG is detected, and the LMA for buffering the
packet transmitted to the corresponding MN when receiving a request
for the packet buffering.
[0055] The foregoing descriptions of specific embodiments of the
present invention have been presented for purposes of illustration
and description. They are not intended to be exhaustive or to limit
the invention to the precise forms disclosed, and obviously many
modifications and variations are possible in light of the above
teaching. Therefore, it is intended that the scope of the invention
be defined by the claims appended thereto and their
equivalents.
[0056] Although a few embodiments of the present invention have
been shown and described, the present invention is not limited to
the described embodiments. Instead, it would be appreciated by
those skilled in the art that changes may be made to these
embodiments without departing from the principles and spirit of the
invention, the scope of which is defined by the claims and their
equivalents.
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